NO.PZ2023010401000140
问题如下：
Assuming its trading partner does not retaliate, which of the following conditions must hold in order for a large country to increase its national welfare by imposing a tariff?选项：
A.It must have a comparative advantage in the production of the imported good. B.The deadweight loss must be smaller than the benefit of its improving terms of trade. C.It must auction the import licenses for a fee to offset the decline in the consumer surplus. D.解释：
The large country is able to cause the foreign exporter to reduce price in order to retain market share. In the large country, domestic producers gain from higher volume and the government gains from collecting the tariff. The sum of these two gains must exceed the deadweight loss to domestic consumers to achieve a national welfare gain. The change in terms of trade causes income redistribution from the foreign exporter to the domestic producer
中文解析：
这个大国能够使外国出口商降低价格以保持市场份额。在这个大国，国内生产商从更高的产量中获益，政府从征收关税中获益。这两项收益的总和必须超过国内消费者的无谓损失，才能实现国家福利收益。贸易条件的变化导致收入从外国出口商再分配到国内生产者
这里强调大国的原因是什么，如果是小国，会有什么区别
